Mounting structure for a rock cutter wheel

ABSTRACT

The cutter wheel is mounted for rotation about an elongated support shaft. This subassembly is moved endwise towards a first end standard until a mounting pin on either the shaft or the end standard engages a mounting pin socket in the other. A second mounting standard is moved towards the second end of the shaft until a second mounting pin on either the shaft or the second end standard is engageable with a mounting socket formed in the other. The second end standard is bolted or otherwise detachably mounted to its support.

United States Patent Schimel 1 Feb, 12, 1974 MOUNTING STRUCTURE FOR A ROCK 3,679,009 7/1972 Goodfe11ow .1 175/364 CUTTER WHEEL 2,061,933 11/1936 Crum 175/363 610,232 9/1898 Ganswindt 308/18 [75] Inventor: Gordon G. Schimel, Kent, Wash.

[73] Assignee: The Robbins Company, Seattle, Primary Examiner-Charles Myhre w Assistant Examiner-BarryGrossman [22] Filed: Mar. 31,1972 ABSTRACT [2]] Appl' 240034 The cutter wheel is mounted for rotation about an elongated support shaft. This subassembly is moved 52] 0.3. CI 1. 308/15, 175/363, 308/8.2, endwise wwards a first end Standard until a mounting 3 3 pin on either the shaft or the end standard engages a 51 Int. Cl. Fl6c 35/08 mounting P Socket in the other A Second mounting 53 Field f Search" 130 22 74 1 9 207 2 standard is moved towards the second end of the shaft 308/D1G. 10; 175/363, 364, 366, 367, 369 until a second mounting pin on either the shaft or the second end standard is engageable with a mounting [56] References Cited socket formed in the other. The second end standard UNITED STATES PATENTS is bolted or otherwise detachably mounted to its supt. 3,216,513 11/1965 Robbins et a1 308/8.2 por 3,707,315 12/1972 Goodfeliow 308/15 16 Ciaims, 9 Drawing Figures PAIENTED Fin 1 2 I914 SIEET 2 BF 3 MOUNTING STRUCTURE FOR A ROCK CUTTER WHEEL BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to rock cutter wheel assemblies, and in more particular to mounting structure for the cutter wheel.

2. Description of the Prior Art Various ways have been proposed and/or used for mounting rock cutter wheels. One type of mountutilizes an axially removable load pin which spans the space between opposite end portions of a mounting saddle. Examples of these mounts are disclosed by U. S. Pat. No. 3,389,760, granted June 25, 1968 to Wilford V. Morris, and by U. S. Pat. No. 3,449,024, granted June 10, 1969 to Carl L. Lichte. Another knownmount utilizes clamps and bolts for securing a support pin or shaft to the end standards. Examples of this type of mount aredisclosed by U. S. Pat. No.

3,216,523 granted Nov. 9, 1965 to Richard J. Robbins and Douglas F. Winberg, and by US. Pat. No. 3,612,196, granted Oct. 12, 1971 to Robert L. Dixon. US. Pat. No. 3,612,196 also discloses a mount for a gauge cutter of a type which includes a mounting socket formed in a radially outer end standard. Such socket is arranged to receive an end portion of the cutter support shaft or pin, with the opposite end of such shaft or pin being secured to the other end standard by means of the clamps.

SUMMARY OF THE INVENTION The principal object of this-invention is to provide novel mounting structure for a rock cutter wheel adapted to minimize the work effort in assembly and disassembly of the cutter wheels subassembly from its mounting saddle or block.

According tothis invention, a mounting pin and a complementary mounting pin socket is provided at each end of the cutter assembly. The mounting pins may be end portions of a support shaft for the cutter wheel, with the sockets therefor being formed in the end standards. Or, the sockets may be formed in the end'portions' of the support shaft and the mounting pins be carried by the end standards. According to the invention, one of the end standards is relatively fixed and the other is readily removable. Disassembly of a cutter assembly involves detachment and removalof the readily removable end standard from its support, followed by an endwise removal of the cutter wheel subassembly away from the second end standard. Preferably, the second end standard includes a threaded socket coaxially related to the cutter wheel and support shaft axis. An elongated bolt extends axially through the support shaft (and perhaps also through an opening therefor in such standard) and threads into the threaded socket. Tapered mounting pins and mounting pin sockets may be employed, and the elongated connector bolt may be used for drawing the two end standards relatively together and the mounting pins into tight engagement with the mounting pin sockets.

Other features, characteristics and advantages of the present invention are discussed in, or will be apparent BRIEF DESCRIPTION OF THE DRAWING In the drawing like element designations refer to like parts, and:

FIG. 1 is a view of a first embodiment of the cutter assembly showing the mounting base, the end standards and the upper half of the cutter wheel subassembly in axial section, and the lower half of the cutter wheel subassembly in side elevation;

FIG. 2 is an exploded isometric view of the cutter assembly of FIG. 1, with some parts cut away for clarity of illustration;

FIG. 3 is an assembled view of the cutter assembly shown by FIGS. 1 and 2;

FIG. 4 is view like FIG. 1, but of a modified form of cutter assembly; 7

FIG. 5 is a view like FIG. 2, but of the modified cutter assembly shown by FIG. 4;

FIG. 6 is a view like FIG. 3, but of the modified cutter assembly shown by FIGS. 4 and 5;

FIG. 7 is a view like FIGS. 1 and 4, but of a second modified form of cutter assembly;

FIG. 8 is a view like FIGS. 2 and 5, but of the second modified form of cutter. assembly; and

FIG. 9 is an assembled view like FIGS. 3 and 6, but of the second modified form of cutter assembly.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS The cutter assembly shown by FIGS. 1-3 comprises a mounting base 10, a first end standard 12 connected to one end of the base 10, and a second end standard 14 which is detachably connected to the opposite end of the base 10. The base '10 is welded or otherwise secured to a cutter carrier (e.g. a tunneling machine cutterhead) 16.

The two end standards 12, 14 are generally perpendicular to the face of the cutter carrier 16. The mounting structure further includes an elongated support shaft 18 which when mounted is perpendicular to the axis'of rotation of the carrier 16, depicted by the axis nonlimitive embodiments of the invention.

line x in FIG. 1, and extends radially of-thecutter carrier 16.

In each embodiment the demountable portion of the cutter assembly (-i.e. the cutter wheel subassembly) comprises the support shaft 18, a cutter wheel 20, a. pair of combination bearings 22 mounting the cutter wheel 20 for a rotation about the support shaft 18, and a pair of seals 24. By way of typical and therefore nonlimitive example, the support shaft 18 is provided with an enlarged diameter portion 26 at one end thereof, a smaller diameter intermediate portion 28 on which the bearings 22 are supported, and a threaded portion 30 adapted to receive a retainer nut 32. As should be evident, the right end bearing 22 (as pictured in FIG. 1) and an intermediate spacer ring 34 are slipped onto the support shaft 18 from thesmall diameter end thereof.

The cutter wheel 20 is installed, also from the small diameter end of the shaft 18, and is moved endwise until its internal spacer flange 36 is against the installed bearing 22. Next, the second bearing 22 is inserted into place and then the retainer nut 32 is installed.

The illustrated form of cutter wheel 20 comprises an annular rim portion 38, a cutting tire or ring 40 and a retainer ring 42.

It is to be understood that the exact form or makeup of the bearings, the seals and the cutter wheel, and the manner in which these elements are mounted onto the support shaft are not considered to be essential parts of the present invention, but rather are matters which can vary from the forms shown in the illustrated embodiments.

portion of the support shaft 18 constitutes an outwardly tapering mounting pin 46 of complementary taper and size. An internally threaded smaller diameter socket 48 is provided at the base of the mounting pin socket 44. Socket 48 is coaxially related to the mounting pin socket 44, the support shaft 18 and an elongated bolt 50 which extends through an elongated central passageway that is formed in the support shaft 18.

The end standard 14, herein sometimes referred to as the second end standard, is provided with a cylindri cal mounting pin socket 52 which receives a cylindrical mounting pin portion 54 of the support shaft 18. Herein the mounting pin 46 is sometimes referred to as the first end portion of the support shaft or the first mounting pin. The mounting pin 54 is sometimes referred to as the second end portion of the support shaft or the second mounting pin. The mounting socket 44 is sometimes referred to as the first mounting socket and the socket 52 is sometimes referred to as the second mounting pin socket.

The second end standard 14 is shown to be detachably mounted on its end of the mounting base 10. It may include a downwardly depending tenon 56 sized to be snugly received within a mortise 58 formed in the base 10. Such standard 14 may be secured to the base 10 by means of machine bolts 60 which extend through aligned openings in side parts 62, 64 and in the base 10 and is secured in place by nut 66 (FIG. 1).

The lower portion of end standard 14 is split or divided along a plane y which axially bisects the mounting pin socket 52.

Assuming the base 10 is firmly affixed to a cutter carrier (eg a tunnel machine cutterhead such as shown'by FIG. 1 ofthe aforementioned US. Pat. No. 3,612,196) and the end standard 12 is secured to such base 10, the cutter wheel subassembly (support shaft 18, cutter wheel 20, bearings 22, seals 24, etc.) is moved endwise until the mounting pin 46 thereon is engaged within socket 44. This movement does not have to be along a straight path but may be along an arcuate path. Next, the end standard 14 is moved relative to the cutter wheel subassembly until the support shaft end portion 54 is received within the mounting socket 52. The recess 58 is open at its end so that the tenon 56 can slide into it during the above described movement of standard l4.

The elongated bolt 50 is inserted first through an opening in a cover cap 68 and then through the elongated central passageway in the support shaft 18. The bolt 50 is tightened to draw the cutter wheel subassembly tightly against end standard 12 and the mounting pin 46 snugly within the socket 44. Next, the bolts 60 are installed and the nuts 66 are attached. When the bolts 60 are tightened down the two portions of the end standard 14 are moved relatively closer together at the split, resulting in the walls of the socket 52 frictionally gripping or clamping the periphery of the mounting pin 54. The cover cap 68 is provided merely for the purpose of protecting the bolt head 70. As shown by FIGS. l-3, the bolt head 70 is housed within a countersink 72 formed in the cap 68.

The embodiment of FIGS. 4-6 will now be described. The cutter wheel 20 and most of the elements serving to mount it for rotation about the support shaft 18 are identical to those described in connection with the embodiments of FIGS. 1-3. Therefore, the elements will not again be described and only reference numeral 20 will be used in FIGS. 4-6 in connection with the cutter wheel.

In this embodiment inwardly tapering mounting pin sockets 96, 82 are provided in each of the end standards 12, 14' and a complementary outwardly tapering mounting pin 74, 76 is provided at each end of the support shaft 18. In this form, the mounting pin 76 and the retainer nut for the bearings, etc. are integrated into a single member. Such member 76 is threaded onto the small diameter end of the support shaft 18.

The initial portion of the assembly procedure for this embodiment is identical to the initial portion of the assembly procedure for the embodiment shown by FIGS. 1-3. However, in this form a downwardly opening trapezoidal mortise 78 is formed in the end standard 14'. Mortise 78 is adapted to receive a complementary tenon 80 which projects endwi'se outwardly from the base 10'. The mortise 78 is aligned with the tenon 80 and the end standard 14 is moved towards the partially mounted cutter wheel subassembly until the tenon 80 is loosely engaged by the mortise 78 and the mounting pin 76 is loosely within the mounting socket 82. Next, the connector bolt 50 is inserted through first an opening 84 in end standard 14' and then through the central passageway 86 in the support shaft 18'. The bolt 50 is rotated to thread its threaded end portion 48 into the threaded socket 90. As the bolt 50 is tightened its head 70 enters into a countersink 94 provided in end standard 14' about the opening 84. Ultimately, the head 92 bears against the base of the countersink 94so that when the bolt 50 is tightened further it forces the end standard 14 closer to end standard 12', and the mounting pins 74, 76 into snug engagement'within their respective sockets 96, 82; Finally, a cross bolt 98 is tightened to draw the two lower side parts 100, 102 of the end standard 14 toge'ther and into gripping engagement with the tenon 80. In this embodiment the end standard 14 is provided with a gap 104 in the region thereof above the tenon 80 and the bolt 98 extends through a passageway provided for it also above the tenon 80 along an intersecting path with the gap 104. The part of such bolt passageway within end standard part is internally threaded to receive the threads of the bolt 98. A countersink 106 is provided for the head 108 of bolt 98.

An advantage of the embodiment shown by FIGS.

4-6 is that there are no exposed bolt heads which can be abraided during use of the cutter. Also, there are no bolt heads in the region of the end standards 12, 14' which are closest to the rock face being cut.

The mounting structure shown by FIGS. 7-9 is quite similar to the mounting structure which has just been described in connection with FIGS. 4-6. Therefore, only the difi'erences will be discussed in detail. Also, in this form the cutter wheel 20, the bearings 22, the seals 24, etc. willnot be described again, and only reference numeral 20 will be used in the drawing figures.

In this embodiment the support shaft 18" is tubular in form and includes an inwardly tapering mounting pin socket 110, 112 at each of its ends. Socket 110 is adapted to mate with a complementary inwardly tapering mounting pin 114 which is a part of end standard 112". A second inwardly tapering mounting pin 116 is carried by the second end standard 14". In this embodiment a transverse passageway 118 is provided through the tenon 80'. This passageway 118 is alignable with a bolt receiving passageway 120 formed through the lower side portions 122, 124 of the end standard 14" when the tenon 80 is within the mortise 78'. Passageway 118 is wider than the diameter of the cross bolt 98, so that the end standard 14 can be adjusted in position axially of the support shaft 18" while the cross bolt 98 is engaged within both passageway 118 and passageway 120.

Assembly commences by the workmen moving the cutter wheel subassembly relatively toward the end standard 12, to place the mounting pin 114 within its mounting socket 110. Next, the end standard 14 is moved into place, with the tenon 80 entering into mortise 78' and the mounting pin 116 entering into mounting pin socket 112. The main connector bolt 50 is inserted first through its opening in standard 14", then through the open center of the support shaft 18, and is threaded into the internally threaded socket 126 formed in end standard 12', coaxially with the mounting pin 114. The bolt 50 is tightened for the purpose of drawing the mounting pins 114, 116 into tight engagement with the mountingpin sockets 110, 1 12. Next, the cross bolt 98 is tightened for the purpose of squeezing the two clamp parts 122, 124 together and into tight engagement with the tenon 80.

The embodiment of FIGS. 7-9 is characterized by having only two bolt heads and both of them are countersunk into the end standard 14", so that they are protected against wear.

From the foregoing, further variations, modifications, adaptations and usages of the cutter wheel mounting structure of this invention will be apparent, within the scope of the following claims.

What is claimed is:

1'. Mounting structure for a rock cutter wheel, comprising:

an elongated support shaft having first and secon end portions and a central passageway extending axially therethrough;

a first end standard;

a first mounting pin on one of said first end portion and said first end standard and a complementary first mounting pin socket in the other, said mounting pin and said mounting pin socket being oriented to be engageable by a movement of said support shaft endwise towards said first end standard;

a second end standard including means for detachably connecting it to its support in spaced relation from the first end standard;

a second mounting pin on one of said second end position and said second end standard and a complementary second mounting pin socket in the other;

a threaded socket in said first end standard alignable with the central passageway in said support shaft; and

an elongated bolt insertable through the central passageway in said support shaft, said bolt having a threaded end portion which is threadable into said threaded socket, so that said bolt can be used to secure the support shaft to at least said first end standard.

2. Mounting structure according to claim 1, further comprising a base to which said first end standard is secured, and wherein the means for detachably connecting the second end standard to its support comprises machine bolt means for removably securing the second end standard to said base.

3. Mounting structure according to claim 2, wherein the first and second end portions of the support shaft include the said first and second mounting pin sockets and the said first and second mounting pins are on the first and second end standards.

4. Mounting structure according to claim 2, wherein the first and second end portions of the support shaft include the said first and second mounting pins and the mounting pin sockets are formed in the first and second end standards.

5. Mounting structure according to claim 4, wherein said first end standard is divided into two parts and the separation between the two parts occurs along a plane which passes axially through the mounting pin socket in such end standard.

6. Mounting structure for a rock cutter wheel, comprising:

'an elongated support shaft having an outward tapering mounting pin at each of its ends;

a mounting base;

a first end standard secured to said mounting base and including a complementary first mounting pin socket for receiving the first mounting pin, by a movement of said support shaft endwise towards said first end standard;

a second end standard including means for detachably connecting it to said base in spaced relation from the first end standard and a complementary second mounting pin socket for receiving said second mounting pin, by a movement of said second end standard axially of said support shaft.

7. Mounting structure according to claim 6, wherein said mounting base includes a tenon projecting outwardly at the second standard end thereof and said second standard includes a mortise for receiving said tenon.

8. Mounting structure according to claim 7, wherein said second end portion includes inwardly compressible side portions defining said mortise and means for compressing said side portions into tight engagement with the tenon.

9. Mounting structure according to claim 6, wherein said first end standard includes a threaded socket extending coaxially with the second mounting pin socket, said elongated support shaft includes a central passageway extending axially therethrough, and said mounting structure includes an elongated bolt insertable through the central passageway in said support shaft, said bolt having a threaded end portion which is threadable into said threaded socket, so that said bolt can be used to secure the support shaft to at least said first end standard.

l0. Mounting structure for a rock cutter wheel, comprising:

an elongated support shaft having an inward tapering mounting pin socket at each of its ends;

a mounting base;

a first end standard secured to said base and including a complementary first mounting pin for insertion into the first mounting pin socket, by a movement of said support shaft endwise toward said first end standard;

a second end standard including means for detachably connecting it to said base in spaced relation from the first end standard and a complementary second mounting pin for insertion into said second mounting pin socket, by a movement of said second end standard axially of said support shaft.

11. Mounting structure according to claim 10, wherein said mounting base includes a tenon projecting outwardly at the second standard end thereof and said second standard includes a mortise for receiving said tenon.

12. Mounting structure according to claim 11, wherein said second end portion includes inwardly compressible side portions defining said mortise and means for compressing said side portions into tight engagement with the tenon.

l3. Mounting structure according to claim 10, wherein said first end standard includes a threaded socket extending coaxially with the second mounting pin, said elongated support shaft includes a central passageway extending axially therethrough, and said mounting structure includes an elongated bolt insertable through the central passageway in said support shaft, said bolt having a threaded end portion which is threadable into said threaded socket, so that said bolt can be used to secure the support shaft to at least said first end standard.

l4. Mounting structure for a rock cutting wheel,

comprising:

an elongated support shaft having first and second end portions; a mounting base; a first end standard secured to said mounting base; a first mounting pin on one of said first end portion and said first end standard and a complementary first mounting pin socket in the other, said mounting pin and said mounting pin socket being oriented to be engageable by a movement of said support shaft endwise towards said first end standard;

a tenon extending outwardly from said mounting base at the end thereof opposite the first end standard;

a second end standard including means for detachably connecting it to said mounting base in spaced relation from the first end standard, said means comprising compressible side parts defining a mortise for receiving said tenon and means for compressing said side parts for the purpose of clamping them in tight engagement with said tenon;

a second mounting pin on one of said second end portion and said second end standard and a complementary second mounting pin socket in the other, said second mounting pin and said second mounting pin socket being engageable by a movement of said second end standard so as to position said tenon within said mortise.

l5. Mounting structure according to claim 14, wherein said elongated support shaft also includes a central passageway extending axially therethrough, a threaded socket is formed in said first end standard and is alignable with the central passageway in support shaft, and said mounting structure includes an elongated bolt insertable through the central passageway in said support shaft, said bolt having a threaded end portion which is threadable into said threaded socket, so that said bolt can be used to secure the support shaft to at least said first end standard.

16. Mounting structure according to claim 15, wherein said second end standard includes a bolt receiving opening extending therethrough which is in alignment with the central passageway of the elongated support shaft when said mounting pins are within the mounting pin sockets, and said elongated bolt includes a head portion of larger dimension than the bolt opening, so that when such bolt is tightened its head portion will bear against the second end standard and move it towards the first end standard. 

1. Mounting structure for a rock cutter wheel, comprising: an elongated support shaft having first and second end portions and a central passageway extending axially therethrough; a first end standard; a first mounting pin on one of said first end portion and said first end standard and a complementary first mounting pin socket in the other, said mounting pin and said mounting pin socket being oriented to be engageable by a movement of said support shaft endwise towards said first end standard; a second end standard including means for detachably connecting it to its support in spaced relation from the first end standard; a second mounting pin on one of said second end position and said second end standard and a complementary second mounting pin socket in the other; a threaded socket in said first end standard alignable with the central passageway in said support shaft; and an elongated bolt insertable through the central passageway in said support shaft, said bolt having a threaded end portion which is threadable into said threaded socket, so that said bolt can be used to secure the support shaft to at least said first end standard.
 2. Mounting structure according to claim 1, further comprising a base to which said first end standard is secured, and wherein the means for detachably connecting the second end standard to its support comprises machine bolt means for removably securing the second end standard to said base.
 3. Mounting structure according to claim 2, wherein the first and second end portions of the support shaft include the said first and second mounting pin sockets and the said first and second mounting pins are on the first and second end standards.
 4. Mounting structure according to claim 2, wherein the first and second end portions of the support shaft include the said first and second mounting pins and the mounting pin sockets are formed in the first and second end standards.
 5. Mounting structure according to claim 4, wherein said first end standard is divided into two parts and the separation between the two parts occurs along a plane which passes axially through the mounting pin socket in such end standard.
 6. Mounting structure for a rock cutter wheel, comprising: an elongated support shaft having an outward tapering mounting pin at each of its ends; a mounting base; a first end standard secured to said mounting base and including a complementary first mounting pin socket for receiving the first mounting pin, by a movement of said support shaft endwise towards said first end standard; a second end standard including means for detachably connecting it to said base in spaced relation from the first end standard and a complementary second mounting pin socket for receiving said second mounting pin, by a movement of said second end standard axially of said support shaft.
 7. Mounting structure according to claim 6, wherein said mounting base includes a tenon projecting outwardly at the second standard end thereof and said second standard includes a mortise for receiving said tenon.
 8. Mounting structure according to claim 7, wherein said second end portion includes inwardly compressible side portions defining said mortise anD means for compressing said side portions into tight engagement with the tenon.
 9. Mounting structure according to claim 6, wherein said first end standard includes a threaded socket extending coaxially with the second mounting pin socket, said elongated support shaft includes a central passageway extending axially therethrough, and said mounting structure includes an elongated bolt insertable through the central passageway in said support shaft, said bolt having a threaded end portion which is threadable into said threaded socket, so that said bolt can be used to secure the support shaft to at least said first end standard.
 10. Mounting structure for a rock cutter wheel, comprising: an elongated support shaft having an inward tapering mounting pin socket at each of its ends; a mounting base; a first end standard secured to said base and including a complementary first mounting pin for insertion into the first mounting pin socket, by a movement of said support shaft endwise toward said first end standard; a second end standard including means for detachably connecting it to said base in spaced relation from the first end standard and a complementary second mounting pin for insertion into said second mounting pin socket, by a movement of said second end standard axially of said support shaft.
 11. Mounting structure according to claim 10, wherein said mounting base includes a tenon projecting outwardly at the second standard end thereof and said second standard includes a mortise for receiving said tenon.
 12. Mounting structure according to claim 11, wherein said second end portion includes inwardly compressible side portions defining said mortise and means for compressing said side portions into tight engagement with the tenon.
 13. Mounting structure according to claim 10, wherein said first end standard includes a threaded socket extending coaxially with the second mounting pin, said elongated support shaft includes a central passageway extending axially therethrough, and said mounting structure includes an elongated bolt insertable through the central passageway in said support shaft, said bolt having a threaded end portion which is threadable into said threaded socket, so that said bolt can be used to secure the support shaft to at least said first end standard.
 14. Mounting structure for a rock cutting wheel, comprising: an elongated support shaft having first and second end portions; a mounting base; a first end standard secured to said mounting base; a first mounting pin on one of said first end portion and said first end standard and a complementary first mounting pin socket in the other, said mounting pin and said mounting pin socket being oriented to be engageable by a movement of said support shaft endwise towards said first end standard; a tenon extending outwardly from said mounting base at the end thereof opposite the first end standard; a second end standard including means for detachably connecting it to said mounting base in spaced relation from the first end standard, said means comprising compressible side parts defining a mortise for receiving said tenon and means for compressing said side parts for the purpose of clamping them in tight engagement with said tenon; a second mounting pin on one of said second end portion and said second end standard and a complementary second mounting pin socket in the other, said second mounting pin and said second mounting pin socket being engageable by a movement of said second end standard so as to position said tenon within said mortise.
 15. Mounting structure according to claim 14, wherein said elongated support shaft also includes a central passageway extending axially therethrough, a threaded socket is formed in said first end standard and is alignable with the central passageway in support shaft, and said mounting structure includes an elongated bolt insertable through the central passageway in said support shaft, said bolt having a threaded end portion which is threadable into said threaded socket, so that said bolt can be used to secure the support shaft to at least said first end standard.
 16. Mounting structure according to claim 15, wherein said second end standard includes a bolt receiving opening extending therethrough which is in alignment with the central passageway of the elongated support shaft when said mounting pins are within the mounting pin sockets, and said elongated bolt includes a head portion of larger dimension than the bolt opening, so that when such bolt is tightened its head portion will bear against the second end standard and move it towards the first end standard. 